When the call was made for the dawn prayer, the Messenger of Allah ﷺ would pray two short rakats before rising to perform the prayer.
حدثنا محمد بن رمح أنبأنا الليث بن سعد عن نافع عن ابن عمر
أن رسول الله ﷺ كان إذا نودي لصلاة الصبح ركع ركعتين خفيفتين قبل أن يقوم إلى الصلاة
Reported by Bukhari, Adhan, Chapter: The Adhan After Fajr, no. 618, 1181, 1173, and Muslim, Prayer of the Traveler, Chapter: The Recommendation of the Two Sunnah Units of Fajr and the Encouragement to Perform Them, etc., no. 723, from the hadith of Nafi, through him.